This invention relates to optical connectors and, more particularly, to optical jacks that include electrical connectors.
The growth in optical communications has been fueled by the extraordinary bandwidth that is available on optical fiber. Such bandwidth enables thousands of telephone conversations and television channels to be transmitted simultaneously over a hair-thin fiber that is made from a high-quality glass material. Nevertheless, bandwidth alone cannot satisfy some very simple needs that are easily handled by electrical cables. For example, electrical signals are the only practical way to interact with the existing communications infrastructure (e.g., standard telephone equipment) or even to operate a simple indicator lamp. And so it seems likely that the most desirable cables will combine electrical wires and optical fibers to enable designers to take maximum advantage of the strengths of each media. And while hybrid (i.e., electrical/optical) cables exist, hardware for connecting such cables to other communication equipment is presently too large, too costly or too cumbersome.
For example, patch panels are used to interconnect specific customers and equipment with other specific customers and equipment, and it is imperative that the connections be made accurately. One system is shown in U.S. Pat. No. 5,394,503, which discloses an optical fiber patch cable having end connectors that are arranged to operatively connect with patch panel couplings. Each patch cable includes one or more optical fibers and one or more electrical conductors. However, these end connectors and couplings are relatively bulky with large cross-section areas, each having many individual parts that do not yield to machine assembly. Consequently, they are neither space nor cost effective. Space is at a premium in such patch panels and an optical/electrical connector arrangement having a small footprint (i.e., cross-section area) is desirable, as is the ability to easily insert and remove closely spaced connectors in the patch panel.
Other hybrid jack receptacles are known in the art and shown in: U.S. Pat. Nos. 5,109,452; 5,159,651; 5,473,715 and 5,745,622. However, none of these receptacles provides the desired cost and space effectiveness. Some receptacles have multiple latches while others require twisting, which means that additional separation between connectors is required so that an installer""s fingers can be positioned on both sides of the connector during installation and removal.
Another deficiency associated with known hybrid connectors is that too much effort is required align the plug connector with the jack receptacle during installation because both electrical and optical connections need to be simultaneously engaged. This is the natural result of attempting to align a large number of connections at the same time.
Accordingly, what is desired is a jack receptacle for receiving a plug connector containing optical and electrical transmission media. Desirably, the receptacle should have a relatively small cross-section area so that it can be used in densely populated panels, be adaptable for mounting on a printed wiring board. Moreover, it should facilitate alignment with the plug connector during installation.
The above-described deficiencies are overcome by a jack receptacle for receiving a plug connector containing an optical fiber and at least one electrical wire. The receptacle includes an optical port that is formed by a cavity having a generally rectangular entrance at its front end that is shaped to receive the plug connector. A boss is located at the back end of the cavity along its central axis for receiving an optical fiber, which may be a glass fiber within a ferrule or a plastic fiber. Finally, a retaining surface is molded into a top surface of the cavity for holding the plug connector therein. Additionally, the jack receptacle includes an electrical port for making electrical contact with at least one metallic terminal in the plug connector. The electrical port includes a conductor that is positioned substantially at a bottom surface of the cavity at the entrance to the optical port.
In illustrative embodiments of the invention, the jack receptacle includes four conductors and is arranged to receive one optical fiber. The jack receptacle illustratively includes a pair of back-to-back cavities that are axially aligned with a circular opening that extends between the cavities for the passage of optical signals.
In one illustrative embodiment, both cavities are identical to each other in that they are designed to receive identical plug connectors containing an optical fiber and at least one electrical wire. In another illustrative embodiment, one of the cavities contains a transducer for converting optical signals into electrical signals or vice versa.
In some illustrative embodiments, the conductors extend between the front ends of the back-to-back cavities and are electrically connected to each other; in other illustrative embodiments, the conductors are not connected to each other, but rather extend away from the jack receptacle to facilitate insertion into a printed wiring board.
Advantageously, the length of each cavity in the longitudinal direction is greater than the width of its entrance, and this helps to align the plug connector prior to electrical contact.